Looking for information on making the interior engine cover area less noisy on my Motorhome.

Everytime the fan clutch kicks on the sound from sitting on top of the engine is very loud. I can hear the roar of the motor and know that someone has made there rig alot quieter.

Has anyone taken the time to try and quiet there rig down? What have you done and what did it cost? I hope this thread gets alot of exchanges.

The time spent doing a project like this is well worth it to me.

------------------
http://www.truckroadservice.com/

I like Sound Stop foam. It consists of a layer of mineral weighted vinyl between two layers of soft foam with a mylar layer on one side. It has the virtue of preventing the passage of both sound and heat through it. Defender Marine sells it in 1/2 and 1 inch thicknesses, with the 1 inch costing $51 for 12 square feet. Being loaded at 1 lb/sq ft, it will cut about 70% of the airborne sound, with an STC of 19.

A better, but more expensive product is Marine grade Ultra Barrier from http://www.soundprooffoam.com It is 1 1/8 thick and, being loaded at 2 lbs/sq ft, will block over 95% of the noise, and even more of the lower frequencies. It offers the most sound reduction for the money, by far, costing $9.59 per sq ft delivered. It has a STC of 32. It does not, however, have a layer of Mylar for heat insulation, so I would glue a mylar survival blanket to the face after installation. They have a cheaper, non-marine grade Ultra Barrier that is $7.34 per sq ft delivered, and it might be adequate with a survival blanket over it.


It comes in a 4 by 8 sheet which is twice what is needed, so I would like to split the cost ($307) with another Barther in Southern California if possible. Or someone who is going to Quartzsite in Jan.

Another product is Lcomp from www.B-quiet.com It works out to $11.87 per sq ft delivered, and is availble in 8 sq ft sheets, so might be more attractive, even though its unit price is higher and its STC is lower. It has an STC of 30.

JC Whitney sells http://www.jcwhitney.com/aut oparts/Product/tf-Browse/s-10101/Pr-p_Product.CATENTRY_ID:2002966/showCustom-0/p-2002966/N-111+600002663+10201/c-10101 , but I have some on my shelf and the layers have become delaminated just sitting there, so I would question its quality. I did, however, have good results when I used it on a boat. I do not know its loading, but would suspect it to be 1 lb/sq ft.

I like the underside lined with 1 inch composite foam/vinyl and then a throw rug that fits over the doghouse The throw rug has a layer of http://www.soundprooffoam.com/quiet-barrier.html or Volara from http://www.foambymail.com/VolaraSP.html glued to its underside, and is large enough to overlap the joint where the doghouse meets the floor. I had to let the one I made go with my last SOB. It would be very sexy to make a fitted carpet cover with a loaded vinyl liner to drop over the doghouse.

I have converted to a shorter air cleaner (same height as a 454 truck), and am going to build a new, lower, doghouse with a flat top for the dog to sleep on. When I do, I will pay particular attention to having a very tight gap sealed with closed-cell foam, and an overlap of plywood inside to block sound transmission through the gap.

To see (or hear) how much noise is coming through the gap, take a throw rug with you. Fold it up and lay it on the doghouse and judge its quieting effect. Then unfold it and lay it so it covers the gap. You might just find that a heavy throw rug is enough.



[This message has been edited by bill h (edited August 09, 2005).]

Hey Bill, I was wondering if you ever got around to making that lower doghouse, and if so do you have and schematics or advice?

I am planning to tackle noise reduction this summer... doghouse liner, floor (over the wheel wells) and firewall. I am still researching the options above, also some of my boat friends have tried various materials that I want to compare. Good luck with yours.

I have found that just sealing the doghouse gaps made a BIG difference.

You might look into Acoustiblok products. I've had good experience with their stuff in a non-automotive installation. See http://www.acoustiblok.com/aut...ve-soundproofing.php